Rain Water Harvesting
System
&
Management
Presented By
Presented
By
A K Kanotra
Siel Chemical Complex
Contents
Introduction
Concept and Technology of Rainwater Harvesting
Average Rainfall of States in India
Availability of Rainwater Through Roof Top Rainwater Harvesting
Runoff Coefficients for Various Catchments Surfaces
Rainwater Harvesting System
Treatment Techniques
Materials for Rainwater Tanks
Rainwater Harvesting System at Siel Chemical Complex
Introduction
Every year, the water level in the state
PUNJAB goes down by one meter. If this
continues, the state will soon turn into a
desert. So it is necessary to save every drop of
water.
“Every commercial building as well as big
houses in the state must install Rain water
harvesting system to save water”
What is rain water harvesting ?
• It is the activity of direct collection of
rain water
• Rain water can be stored for direct use
or can be recharged into the ground
water aquifer
Rain Water in India
• Total annual rainfall in India: 400 million hectaremeters (area x height)
• India’s area: 329 million hectares
• If evenly spread, average height: 1.28m
• Actual distribution:
– Highly skewed area-wise
– The desert receives less than 200mm annually,
while Cherrapunji receives 11,400mm
– But almost every part of India receives at least
100mm annually
• Key: even 100mm annual rainfall sufficient if
harvested properly and where it falls
But…
.
• Temporal distribution of rain in India also skewed
• Rainfall in India seasonal (unlike Western countries)
• Most of the country receives rainfall only for about
100 hours each year
– Rough rule of thumb: #cm of rain = #hours rain
received
– E.g.: Jodhpur receives 40cm of rain in about 40
hours
• Natural implication of such skew:
– Most of the rain water lost due to runoffs
– Unlike the west, very little water percolates into
the ground
– Hence, the importance of harvesting structures
for local self-sufficiency
Average Rainfall of States in India
Average annual
Sl.No.
State
Meteorological Divisions
rainfall (mm)
1
Andaman and
Nicobar
Andaman and Nicobar Islands
2,967
2
Arunachal
Pradesh
Arunachal Pradesh
2,782
3
Assam
Assam and Meghalaya
2,818
4
Meghalaya
Assam and Meghalaya
2,818
5
Nagaland
Nagaland, Manipur, Mizoram an Tripura
1,881
6
Manipur
Nagaland, Manipur, Mizoram andTripura
1,881
7
Mizoram
Nagaland, Manipur, Mizoram andTripura
1,881
8
Tripura
Nagaland, Manipur, Mizoram andTripura
1,881
Sub-Himalayan West Bengal and Sikkim
2,739
9
West Bengal
Gangetic West Bengal
1,439
10
Sikkim
Sub-Himalayan West Bengal and Sikkim
2,739
Average annual
Sl. No.
11
12
State
Meteorological Divisions
Orissa
Bihar
rainfall (mm)
Orissa
1,489
Bihar Plateau
1,326
Bihar Plains
1,186
Uttar Pradesh
1,025
Plain of West Uttar Pradesh
896
Hills of West Uttar Pradesh
1,667
13
Uttar Pradesh
14
Haryana
Haryana, Chandigarh and Delhi
617
15
Delhi
Haryana, Chandigarh and Delhi
617
16
Chandigarh
Haryana, Chandigarh and Delhi
617
17
Punjab
Punjab
649
18
Himachal Pradesh
Himachal Pradesh
1,251
19
Jammu
Kashmir
Jammu and Kashmir
1,011
20
Rajasthan
and
West Rajasthan
313
East Rajasthan
675
Average annual
Sl. No.
21
State
Madhya Pradesh
Meteorological Divisions
rainfall (mm)
Madhya Pradesh
1,017
East Madhya Pradesh
1,338
Gujarat region
1,107
22
Gujarat
Saurashtra and Kachchh
23
Goa
Konkan and Goa
3,005
Konkan and Goa
3,005
24
Maharashtra
578
Madhya Maharashtra
901
Marathwada
882
Vidarbha
Coastal Andhra Pradesh
1,034
1,094
Telengana
961
25
Andhra Pradesh
Rayalaseema
680
26
Tamil Nadu
Tamil Nadu and Pondicherry
998
27
Pondicherry
Tamil Nadu and Pondicherry
998
Coastal Karnataka
3,456
North Interior Karnataka
731
28
Karnataka
South Interior Karnataka
1,126
29
Kerala
Kerala
3,055
30
Lakshadweep
Lakshadweep
1,515
As per CENTRAL GROUND WATER AUTHORITY (Constituted under sub-section (3) of section 3 of the
Environment (Protection) Act, 1986),NOC for Ground Water withdrawal will be considered for
Industries/Infrastructure projects which are either NEW or under EXPANSION as per the criteria given
below:
Category
Recycle/Reuse
Withdrawal permitted
(% of proposed recharge)
Safe
Mandatory recycling
and reuse of water
NOC is required for groundwater
withdrawal if quantity of groundwater
abstraction exceeds 100 m3/day. AR to
groundwater to be adopted.
However, Industries under B-VI have
no exemption from obtaining NOC.
Semi-critical
Major and Medium
industries shall recycle
and reuse at least
50% of the waste
water
Withdrawal may be permitted subject to
undertaking of recharge** measures.
The withdrawal should not exceed
200% of the recharged quantity.
Critical
Major and Medium
industries should fully
recycle and reuse the
waste water
Withdrawal may be permitted subject to
undertaking of recharge** measures.
The withdrawal should not exceed
100% of the recharged quantity.
Overexploite
d
Full utilization of
recycled water and
reuse of water should
be mandatory
Withdrawal may be permitted subject to
undertaking of recharge** measures.
The withdrawal should not exceed 50%
of the recharged quantity.
Why Rain water harvesting
• To conserve & augment the storage of
ground water
• To reduce water table depletion
• To improve the quality of ground
water
• To arrest sea water intrusion in
coastal areas
• To avoid flood & water stagnation in
urban areas
4
Concept and Technology of Rainwater Harvesting
Rainwater is a free source of nearly pure water and rainwater
harvesting refers to collection and storage of rainwater and other
activities aimed at harvesting surface and ground water. It also
includes prevention of losses through evaporation and seepage and
all other hydrological and engineering interventions, aimed at
conservation and efficient utilization of the limited water. In general,
water harvestings the activity of direct collection of rainwater. The
rainwater collected can be stored for direct use or can be recharged
into the ground water.
There are two main techniques of rain water harvestings.
• Storage of rainwater on surface for future use.
• Recharge to ground water.
RAIN WATER HARVESTING
Rain
Rooftop Water
Roof Top
Filtration
or
Storage
Recharge to ground water
Technology of Rainwater Harvesting
Example of Small level Rain Water
harvesting in villages in India
Availability of Rainwater Through Roof Top
Rainwater Harvesting
Water available from Roof = Annual rainfall (in mm) x roof area (in
sq. m) x co-efficient of run off for roof
Suppose the system has to be designed for meeting drinking water
requirement of a 5-member family living in a building with a
rooftop area of 100 sq.m. Average annual rainfall in the region is
600 mm. Daily drinking water requirement per person (drinking
and cooking) is 10 liters.
We shall first calculate the maximum amount of rainfall that can
be harvested from the rooftop .Following details are available:
Area of the catchments (A) = 100 sq.m.
Average annual rainfall (R) = 600 mm (0.6 m)
Runoff coefficient (C) = 0.85
Annual water harvesting potential from 100 sq.m. roof
=AxRxC
= 100 x 0.6 x 0.85
= 51 cu.m. (51,000 ltr)
The tank capacity has to be designed for the dry period, i.e., the
period between the two consecutive rainy seasons.
With the rainy season extending over four months, the dry season
is of 245 days. Particular care must be taken to ensure that
potable water is not contaminated by the collected rainwater.
Drinking water requirement for the family
(dry season) = 245 x 5 x 10
= 12,250 ltr.
As a safety factor, the tank should be built 20 per cent larger than
required, i.e., 14,700 ltr. This tank can meet the basic drinking
water requirement of a 5-member family for the dry period.
co-efficient of run off
GI sheet
0.90
Asbestos
0.80
Tiled
0.75
Plaster on bricks/
Concrete
0.70
All rainwater-harvesting systems comprise six basic
components irrespective of the size of the system.
1. Catchments area/roof: The surface upon which the rain falls;
the roof has to be appropriately sloped preferably towards the
direction of storage and recharge.
2. Gutters and downspouts: The transport channels from
catchments surface to storage; these have to be designed
depending on site, rainfall characteristics and roof
characteristics.
3. Leaf screens and roof washers: The systems that remove
contaminants and debris; a first rain separator has to be put
in place to divert and manage the first 2.5 mm of rain.
4. Storage tanks: Sumps, tanks etc. where collected rain-water
is safely stored or recharging the ground water through open
wells, bore wells or percolation pits etc.
5. Conveying: The delivery system for the treated rainwater,
either by gravity or pump;
6. Water treatment: Filters to remove solids and organic material
and equipment, and additives to settle, filter, and disinfect.
Rain Water Distribution & Management
Treatment Techniques
Screening
Methods
Strainers and
Leaf Screens
Location
Gutters and
Leaders
Results
Prevent leaves
and other
debris from
Settling
Sedimentation Within Tank
Settles
particulate
matter
Filtering
In-line/Multi-Cartridge
Activated Carbon
Reverse Osmosis
Mixed Media
Slow Sand
After Pump
At Tap
At Tap
Separate Tank
Separate Tank
Sieves sediment
Removes chlorine
Removes contaminants
Traps particulate matter
Traps particulate matter
Disinfecting
Boiling/Distilling
Chemical Treatments
Ultraviolet Light
Ozonation
Before use
Within tank
After the activated
carbon filter
Before Tap
Kills
Kills
Kills
Kills
microorganisms
microorganisms
microorganisms
microorganisms
Materials for Rainwater Tanks
Plastic:
Fiberglass: Fiberglass tanks are lightweight, reasonably priced, and long
lasting, making them one of the most popular tanks in contemporary
installations. As with the polyethylene and galvanized tanks, fiberglass
tanks are commercially available and easy to transport. They are available
in a wide range of sizes and can be specified for potable water. Fiberglass
tanks should be coated or constructed to prevent penetration of sunlight
into the tank.
Plastic Liner: Plastic liners are sometimes used to line concrete tanks or
tanks that have developed leaks. These liners can also be used to line lowcost, temporary collection tanks constructed of materials such as plywood.
Plastic liners that are specified for potable use are commercially available.
Polyethylene: In many countries these tanks are commercially available in a
variety of sizes, shapes, and colors, and can be constructed for above or
below ground installations. Polyethylene tanks are gaining popularity due
to their relatively low cost and because they one slightly more durable than
fiberglass with comparable life expectancy. Their light weight makes them
easy to transport and relocate
Metal:
Galvanized steel tanks are also used. These are commercially available
and reasonably priced and are quite popular. They are noted for their
strength, yet are relatively lightweight and easy to move. Corrosion can
be a problem if exposed to acidic conditions; some suppliers provide an
inside liner to guard against this problem. In addition, high and low pH
water conditions can result in the release of zinc.
Rainwater Harvesting System at
Siel Chemical Complex
Rainwater Harvesting System at
Siel Chemical Complex
SIEL Chemical Complex is a Caustic Soda production plant located at
Rajpura. It has ISO 14000 certification and the organization is very much
concerned to improve the Environmental standards within and outside
the premises of company. To improve the Ground water level in the
surrounding areas, organization is trying to implement the Rain Water
Harvesting within the premises.
In SCC, we are having 02 nos units of rain water harvesting . The first
unit of rain water harvesting was installed and taken in operation w.e.f.
July 20,2007.
It is estimated that around 500m3 of water will be charged into the ground
in a year, with an average rainfall of 82 cms .
Rainwater Harvesting System at
Siel Chemical Complex
Here we are considering the only Rooftop of A & PO building, Security
block building and HR and Administrative block building for rainwater
harvesting.
Rooftop area of A&PO building = 304 sq. m.
Rooftop area of security block building = 192 sq. m.
Rooftop area of HR and administrative block building = 662 sq. m.
Total Rooftop Area = 1158sq.m.
Average Rainfall in this region = 82.23 cm.
= .82 m.
Assuming that 60% of total rainfall is effectively harvested.
Volume of water harvested = 1158 X .82 X .6 cu. m.
= 569.736 cu. m.
= 569736 ltr.
So we can save 569 m3. of water annually from above said building
THANK YOU